The precision at the target for barrel-launched projectiles, for example projectiles for artillery, is dependent on a number of factors, such as, for example, meteorological aspects, the exactness of the launcher, and the launch velocity of the projectile, also referred to as V0. Traditionally the accuracy, viewed from the launcher, with regard to deviation in angle is good compared with the deviation in distance. By improving the deviation in distance, it is possible to improve the overall accuracy and precision for the projectile, which increases the prospects of effectively combating the target for which the projectile is intended.
As a result of the braking effect, the precision in distance of the projectile, also referred to as the longitudinal direction, can be improved. At launch the range of fire can be beyond the target and, during the trajectory of the projectile, the braking effect generated by the brake can adapt the range of fire so as to hit the target. The brake, and the braking effect generated by the brake, result in the enablement of guidance in the longitudinal direction. Guidance in the lateral direction is previously known with, for example, customized control members such as fins. Braking is effected with brake panels, which can be constituted by brake panels, brake flaps or fins designed for braking.
EP-1045221-A1 describes an invention which shows an air brake for a projectile having flat extensible panels. When extended, the panels shown in the description create a flat surface against the direction of travel of the projectile so as to create maximum air resistance, based on the size of the panel, and thus high braking effect.
U.S. Pat. No. 4,072,107 describes an invention which discloses a projectile/sub-munition in the form of a missile with adjustable fins designed to both reduce and increase rotation, as well as to brake the missile. The braking system which is shown in the description uses wholly flatly arranged fins to create maximum air resistance and thus high braking effect.
A problem with the said embodiments of a projectile brake is that, when the brake panel/fin is extended, then the extending and extended brake panel/fin produces a Magnus effect, which produces a force which interferes with the projectile and the projectile brake. The Magnus effect is a force which acts on moving and rotating bodies, such as a projectile flying through the air, and is directed at right angles to the direction of travel. When a brake panel is extended, the Magnus effect produces a Magnus torque which affects the trajectory of the projectile.
Further problems which the invention aims to solve emerge in connection with the following detailed description of the different embodiments.